In my experience if you stay around 2,000 AGL, the closer to the airport the better (not much landing/departing traffic that high). If they need a reason why you are doing it, tell them you are doing a sightseeing flight or a photo flight. A lot of controllers (especially if they've been there a while) will know landmarks such as "blah blah university" so they'll know where you want to go. What airport will you be near?